This invention relates to a change-speed maneuvering apparatus incorporated in a vehicle such as a tractor or the like.
There conventionally are vehicles, for instance tractors, each of which are provided, on its vehicle body, with an upright steering-wheel apparatus and on righthand and lefthand sides of and along the steering-wheel apparatus further with an upright main change-speed maneuvering shaft and an actuation shaft for forward-and-rearward running-travel shiftover, wherein the main change-speed maneuvering shaft is operatively connected to a main change-speed apparatus within a transmission case via interlocking means including levers which are maneuvered in rocking rotation on the lefthand side of a lower portion of the steeringwheel apparatus.
It has been the practice, with such conventional construction, to fixedly provide a bracket or brackets on the lefthand side of the lower portion of the steering-wheel apparatus, and to support the interlocking levers, for free rocking rotation, and on a shaft or shafts mounted on the bracket(s), and it has so far been keenly desired to reduce the number of the component parts like the brackets, shafts and so forth.
The support structure as above has also another problem in that it is there required to dispose the interlocking levers and the bracket(s) outwardly apart from the lower portion of the actuation shaft, in order thus to avoid interference with the actuation shaft, and therefore that the portions of the main change-speed maneuvering apparatus and the forward-and-rearward running-travel shiftover maneuvering apparatus, that are around the lower portion of the steeringwheel apparatus, can not be arranged completely close to each other, thus to result in a messy condition.
Besides, it has as well so far been desired to provide effective operative interlocking means for incorporating a so-called shuttle-transmission structure capable of effecting the speed changing in the same step number in either of forward and rearward running travels, while retaining the construction of disposing the main change-speed lever and the forward-andrearward running-travel shiftover lever on the respective diagonnally opposed sides with respect to and along the steeringwheel post.